1. Field of the Invention
The present invention relates to transmission/reception of a facsimile data in a Wireless Local Loop (WLL) system, and more particularly, to a device for transmission/reception of a facsimile data in a WLL system, in which an analog G3 facsimile signal is converted into a CDMA signal format for transmission/reception of the signal.
2. Background of the Related Art
In general, a Wireless Local Loop (WLL) system provides a wireless subscriber line between a switching center and homes or offices, for providing speech, facsimile, and data communication services. Full scale development of the WLL started as problems of frequency efficiency, radio channel quality, build up cost per a subscriber are solved when the semiconductor and radio communication technologies developed in 1980s are combined with the radio frequency technology developed in 1970s.
Unlike a conventional wire network, the WLL system has the advantages of low build up cost and time, and low maintenance costs, while still providing a variety of services, such as excellent communication quality, data, and Integrated Service Digital Network (ISDN) capabilities, and the like. Thus, the WLL system can be used where a new communication service provider intends to secure a subscriber network quickly, or used as a communication infrastructure of a developing country which has a poor wire communication network.
The WLL system is typically provided with telephone sets and a Network Interface Unit (NIU), which makes radio communication between the telephone sets and a switchboard possible. There are two types of WLL systems: the separate type WLL system and the integrated type WLL system. The separate WLL system is provided with a subscriber connector for wire connection to a stationary telephone so that the subscriber who has the stationary telephone set connected to an existing wire network can buy only the subscriber connector and not a telephone set when the subscriber subscribes to the WLL system. The integrated WLL system, on the other hand, is provided with the telephone set and the subscriber connector integrated in hardware for the convenience of the subscriber who has, for example, no stationary telephone set in subscription to the WLL system.
A related art Code Division Multiple Access (CDMA) WLL has a digital facsimile (class 2, 2.0) function for using a personal computer, with the personal computer connected to the NIU. However, since a group 3 (called G3 hereafter) facsimile signal is transmitted on a CDMA audio channel, a normal transmission/reception of the G3 facsimile is difficult. That is, the G3 facsimile transmission, which is a facsimile device using a PSTN for transmission of an A4 size document within approximately one minute by compressing a number of bits to {fraction (1/10)}, has a problem when it is intended to transmit the facsimile data by using PCS or DCN in that normal facsimile data transmission/reception is extremely difficult because of distortion of the facsimile signal coming from difference between the PSTN and PCS or DCN transmission systems.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.